A. Field of the Invention
The present invention relates to improvements in electric fastener driving tools.
B. Description of the Prior Art
Electric tools for driving fasteners such as staples, tacks and the like are well known and widely used. Examples of tools of this character may be found in U.S. Pat. Nos. 3,141,171; 3,172,121; 3,179,866; 3,434,026; and 4,005,812 all assigned to the assignee of the present invention. These tools illustrated in the above-identified patents set forth the basic components of the tool and are incorporated herein by reference.
The prior art tools commonly include a housing that defines a handle portion and a head or nose portion within which a solenoid winding is mounted for accelerating a magnetic armature. Specifically, a control circuit is operated by a switch in the handle portion for energizing the winding. A magazine is carried by the base of the head portion and by the handle for introducing fasteners into a drive track to be driven by a drive blade supported by the armature.
Normally, the armature of the prior art tools is connected to a second armature and to a single cone spring to allow overtravel of the blade and engagement with a bumper. After continued operation of the prior art tool, however, it often occurs that the bumper disintegrates resulting in the armature engaging a portion of the housing destroying the tool.
An additional problem with the typical prior art tool is its inability to be used on different work surfaces. One solution to the problem has been a removable jaw or nosepiece that is secured to the tool and must be removed through the employment of tools in order to secure a different jaw to the workpiece.
Another frequent problem with prior art tools is jamming of fasteners in the magazine assembly requiring complete disassembly of the tool to clear the jam.